Hose Clamp With Rippled Spring Liner

ABSTRACT

An improved hose clamp having an annular band having an inner face, tensioning means, and an annular spring liner; the spring liner having a circumferential shoulder near an edge of the liner; and a central, cylindrical, rippled, contact portion of smaller circumference than the shoulder, and of smaller width than the inner face of the band. The shoulder is adapted to abut the inner face and the contact portion is adapted to contact a hose or other article to be clamped. The ripples may be symmetric, for example, sinusoidal, or asymmetric, such as saw-tooth shaped.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to the field of hose clamp assemblies,more particularly to a spring liner that is associated with a hose clampassembly, and specifically to a spring liner with a central, rippled,hose-contact portion.

2. Description of the Prior Art

Hose clamps are commonly utilized to join together hoses and fittings orconnectors (referred to hereinafter as fittings), for example, withinthe automotive industry. Hose clamps, hose and fittings respond tochanges in ambient temperature and system temperatures based on thethermal properties of the aforementioned components. Differingcoefficients of thermal expansion of these components can result inthermally-induced reductions in clamping force, thus creating thepotential for fluid or gas leakage. In addition, changes in elasticityof the hose materials over time due to creep, compression set, ordeterioration can also reduce the clamping force and create thepotential for fluid leakage.

Various types of spring liners used in conjunction with hose clamps areknown. U.S. Pat. Nos. 7,178,204 and 7,302,741 are exemplary of the art,disclosing a spring liner having two inward projecting ridges with anoutward-projecting ridge in between. The ridges create two zones of veryhigh compression in the hose, while the central ridge area creates azone of lesser compression.

Mention is also made of a co-pending application by the same applicanttitled “Hose Clamp With Flat Spring Liner,” filed on the same day as thepresent application, the contents of which are hereby incorporatedherein by reference.

SUMMARY

It is an aspect of the present invention to provide an improved springliner which allows a hose clamp to self-compensate for changes inelastic properties and diametric changes of the underlying hose andfittings. The invention is directed to an annular spring liner for ahose clamp having a circumferential shoulder near each edge of the linerand a central inwardly-directed circumferential, cylindrical ridge withrippled contact portion there between the two shoulders. The hose clampseats on the shoulders of the liner when the clamp is tensioned. Thus,at least after assembly, and before tensioning of the hose clamp, therippled central ridge is separated from the inner face of the tensioningband of the hose clamp by a gap of fairly uniform thickness. The widthof the rippled contact portion is less than the width of the inner faceof the tensioning band. The width of the rippled contact portion may bein the range from 40% to 75% of the width of the inner face of thetensioning band.

In another embodiment of the invention, the spring liner further has onat least a portion of one or both circumferential edges a radiallyoutwardly-flared flange.

It is another aspect of the present invention to provide an improvedhose clamp assembly having an annular band having an inner face, atensioner disposed to facilitate constriction of the band, and theannular spring liner as described above.

The foregoing has outlined rather broadly the features and technicaladvantages of the present invention in order that the detaileddescription of the invention that follows may be better understood.Additional features and advantages of the invention will be describedhereinafter which form the subject of the claims of the invention. Itshould be appreciated by those skilled in the art that the conceptionand specific embodiment disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present invention. It should also be realized by thoseskilled in the art that such equivalent constructions do not depart fromthe spirit and scope of the invention as set forth in the appendedclaims. The novel features which are believed to be characteristic ofthe invention, both as to its organization and method of operation,together with further objects and advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. It is to be expressly understood, however, thateach of the figures is provided for the purpose of illustration anddescription only and is not intended as a definition of the limits ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form part ofthe specification in which like numerals designate like parts,illustrate embodiments of the present invention and together with thedescription, serve to explain the principles of the invention. In thedrawings:

FIG. 1 is a perspective exploded view of a hose clamp assembly includingclamp and spring liner in accordance with an embodiment of the presentinvention;

FIG. 2 is a partial sectional view of the spring liner of FIG. 1, takenalong section 2-2;

FIG. 3 is a partially fragmented view of a hose clamp assembly includingspring liner, hose, and fitting in accordance with an embodiment of thepresent invention; and

FIG. 4 is a partial sectional view of a spring liner according toanother embodiment of the invention.

DETAILED DESCRIPTION

The present invention provides for a means of reducing the contactsurface area of the inside diameter (ID) of traditional worm-gear hoseclamp in order to increase the unit loading the hose clamp assemblyimparts to the underlying hose or substrate, while increasing the gripof the hose clamp on the underlying hose. The reduction in contactsurface area is achieved by the use of a circular liner that is insertedinto the ID of a hose clamp or tensioning band 1. The cross-section ofthe liner has shoulders 5 with contact surfaces on their outsidediameter (OD) which are together approximately equal in axial extent(width) to the inside surface width of the hose clamp or tensioningband. The edges of the shoulders may project upward towards the hoseclamps or tensioning band at angles to hold the liner captive within thehose clamp or tensioning band ID. The profile of the liner also includesa rippled, but otherwise flat, cylindrical contact portion 7 positionedinward or lower than shoulders 5. By contact is meant that rippledportion 7 is intended to contact the underlying hose or substrate andincrease the force required to force a clamp off of the hose, relativeto a flat liner. This rippled contact surface is narrower than the hoseclamp or tensioning band 1 width and may be in the range of 40% to 75%of the hose clamp or tensioning band width. Two legs 6 bridge betweenthe two shoulders and the lower contact portion 7 of the liner. Theselegs may be symmetrical and are located on either side of the lowercontact surface and project outward at acute angles relative to theclamp centerline, thus reaching to and attaching to the upper shoulders.

The increase in unit loading can also be described as an increase in theradial pressure the clamp exerts on the underlying hose or substrate.The radial pressure (p_(r)) a hose clamp or a tensioned band exerts is afunction of the band tension (T), the band width (w) and the clampingdiameter (d). For any fixed value of “T” and “d”, an increase in “w”will decrease radial pressure, and a decrease in “w” will increaseradial pressure. Manipulation of a simplified hoop stress formula candemonstrate this behavior; 2T=p_(r) w d transposes to p_(r)=2T/(w d).

In addition to increasing a hose clamp or tension bands' radial pressureas a result of the liner's narrower contact width, the liner also canact as a spring, thus providing a thermal-compensating feature for theclamp. The spring effect will be described in more detail later. First,the drawings will be discussed in more detail.

Referring to FIG. 1, a hose clamp is shown comprising an outer annularband 1, and a typical tensioning means 3, 4. FIG. 1 also shows inexploded view rippled spring liner 9 in accordance with the presentinvention. In other embodiments, spring liner 19 is shown in section inFIGS. 2-3 and spring liner 29 in FIG. 4. Spring liner 9, as well asspring liners 19 and 29, is an annular ring with overlapping ends 10.Spring liner 9, 19 and 29 comprise two flat annular circumferentialshoulders 5 near the edges of the liner, a rippled central annularcircumferential contact portion 7 located between two shoulders 5 and ofsmaller circumference than the shoulders, and two annularcircumferential legs 6 there between connecting the edges of shoulders 5to the edges of rippled contact portion 7. FIG's 2 and 4 shows radialheight differential A between the two shoulders 5 and the rippledcontact portion 7. When liner 9, 19, or 29 is inserted into clamp band1, the inner face of band 1 will abut or seat on shoulders 5, and gap Awill result between the outer surface of contact portion 7 and the innerface of band 1 in the absence of clamp tensioning forces. Thus, rippledcontact portion 7 does not abut the inner face of band 1 in the absenceof clamp tensioning forces. The gap, A, is fairly uniform, but for theripples. In other words, the central part of the liner is substantiallyflat, but with the addition of the small ripples. The ripples are aseries of corrugations or small waves that are smaller in amplitude thanthe gap, A, and also smaller in wavelength that the width of the band orthe contact portion 7. Preferably there are at least three ripples inthe rippled portion, or four or more. The ripples appear in crosssections of the liner, i.e. radial sections in a plane parallel to andpassing through the center axis of the clamp.

The terms outward and inward refer to direction with respect to thecenter axis of the generally circular liner. Inward or inner generallymeans directed toward the center axis of the liner. Outward or outergenerally means directed away from the center axis of the liner.

Upon applying clamp tensioning forces, i.e., tightening or tensioning ofthe band, the overlap section 10 of the liner can increase in length,resulting in a decrease in the circumference of the liner. As the bandtightens, the liner is thus pulled into compressive engagement with theassociated hose. FIG. 3 illustrates the hose clamp assembly in use witha hose 11 and a hose fitting 12. Band 1 of the hose clamp seats on thetwo shoulders 5. The inward facing rippled contact portion 7 of theliner creates a zone of relatively uniform compression 14 in the hose.Ripples 17 in the embodiment of FIG. 2 are of generally sinusoidalshape. The ripples will push into the hose surface, increasing the forcerequired to pull the clamp off the hose. Other symmetric ripple profilesmay be advantageously used, such as triangular, trapezoidal, orgenerally curvilinear.

The ripples also are believed to reduce leakage and/or increase thepressure required to produce leakage under the clamp. This effect may bethe result of an increased tortuosity for any gas or liquid moleculetrying to diffuse or permeate out in the region of the ripples.

FIG. 4 shows another embodiment in which ripples 27 are of asymmetricshape, namely saw tooth or triangular shape. An advantage of asymmetric,saw tooth ripples is that the pull-off force is direction-dependent andtherefore the liner can be oriented to maximize the resistance to beingpulled off in a desired direction. Saw tooth ripples 27 in FIG. 4 may becharacterized by the two tooth angles, α and β. In FIG. 4, α and β aredefined with respect to a vertical line. The angle, α, may be set asdesired, for example, in the range of from zero to 50°, or from 5° to40°, or from 5° to about 25°, or about 10°. The angle, β, may be set asdesired, for example, in the range of from 20° to 90°, or from 30° to80°, or from 35° to about 60°, or about 40°.

The profile of the liner is designed so that the two legs 6 can deflectunder the compressive forces, creating a spring effect. As the band istensioned, the deflection of the legs will cause gap A to decrease to A′(A′≦A), or perhaps even disappear completely. As the band is tensioned,the deflection may also cause the rippled contact surface to deformslightly. The decrease in gap is an indication of the amount of springenergy stored in the annular spring liner. The net effect of theseradial and axial deflections and the resulting compression forces on thehose is a much better initial and long term sealing effect than obtainedwith prior art hose clamp liner designs.

As the hose and clamp assembly is exposed to thermal fluctuations, thespring liner can respond by further deflecting or by relaxing, thushelping to maintain an excellent sealing force on the hose assembly. Asthe hose material, which is typically vulcanized rubber, takes on acompression set, or inelastic deformation, due to deterioration ofelastic properties over time, the force exerted by the rubber will relaxor decline, and the spring liner again relaxes or releases some of thestored spring energy, thus maintaining an excellent sealing force on thehose. Compared to prior liner designs with narrow ridges which createzones of very high compression, the present invention creates a moreuniform zone of moderate compression, which may advantageously avoidextreme deformations and extreme effects of compression set in therubber hose being clamped, while still providing a high degree ofmechanical grip on the hose.

If the hose clamp is tensioned to the extent that gap A′ is eliminatedand the outer surface of contact portion 7 contacts the inner surface ofband 1, then any further deflection of the spring liner requires muchhigher forces, commensurate with a dramatic increase in spring rate.Under this condition, the deflection of the spring liner in response tothermal expansion of the hose is very limited. However, under thiscondition, the spring liner's ability to relax or respond to thermalcontraction of the hose is maximized. Thus, the clamp and spring linermay be designed so that in use, gap A′ is maintained even in thepresence of clamp tensioning forces. Alternately, the clamp and springliner may be designed so that in use, the outer surface of the rippledcontact portion 7 may abut the inner face of the hose clamp in thepresence of clamp tensioning forces.

As shown in FIG's 2 to 4, spring liner 19 may also have one or tworadially outward flared flanges 8 to aid in aligning liner 19 withinband 1. The flanges shown in the figures flare outward at about a 45°angle. Any suitable flare angle or flare shape may be used. Flanges 8,as well as legs 6, may be sharply bent or may have a more rounded,gradual transition from the adjoining shoulders 5 or contact portion 7.Flanges 8 may extend the entire circumference of the liner or may be cutshort in appropriate places to reduce interference in the overlapsection 10 of the liner or to reduce interference between the liner andthe tensioning means 3, 4. Alternately, or in addition to a flange, thespring liner may be more or less permanently affixed to band 1 by anymeans that provides an adequate bond, such as, but not limited to, heatwelding, chemical welding, chemical bonding, staking, mechanicalfasteners, or a combination of two or more of the foregoing.

The spring force exerted by the liner depends on the thickness andmodulus of the material of which it is constructed. The force alsodepends on the precise profile, i.e. the shape and size of the legs,contact portion, and shoulders. The profile shown in FIG. 2, when formedout of sheet metal about 0.012 inches (0.3 mm) thick, is suitable fortypical automotive hose clamping applications. One skilled in the artwould be able to alter the materials, material properties, shoulder andrippled surface dimensions, flange angles, overlap distance, and/orspring liner thickness to optimize the rippled spring liner forparticular applications. The profile need not be perfectly symmetric.The two shoulders, the legs, and the central rippled surface may all beof different sizes. The central rippled surface need not be at the exactcenter of the annular liner. The two leg angles may be different. Thethickness of the liner may also vary in the axial direction. One or moreof the shoulders and/or one or more of the legs may also be rippled.

The shoulders need not be broad, flat structures. A shoulder orshoulders may be a circumferential line of contact adapted to abut theinner face of the band of the hose clamp. Such a shoulder could be anoutwardly convex ridge formed near the edge of the liner, or it couldsimply be an edge of the liner. The important feature of the shoulder isthat it be adapted to contact or abut the inner face of the band of thehose clamp. Viewed in section as in FIG. 3, the contact between theinner face of band 1 and shoulder 5 could therefore be a point or aline. In three dimensional terms, the contact between the inner face ofband 1 and shoulder 5 could therefore be a circular line or acylindrical area, depending on the shape of the shoulder.

Friction between the overlapping ends of the spring liner can affect theclamping force achieved during assembly. To reduce the friction force,the overlapping ends may be coated with wax or other suitable lubricant.To increase the friction force, the overlapping section may be cleaned,roughened, grooved, knurled, or the like. Thus, one skilled in the artcan optimize the friction as needed or desired.

Any of the various hose clamp tightening or tensioning means, i.e.,“tensioner,” known in the art may be used. By way of illustration, thetensioning mechanism may be a worm drive 3, 4 as shown in FIG. 1.Alternatively, the tensioner may be a T-bolt, a ratcheting mechanism, abolt and barrel mechanism, a nut and bolt assembly, a permanent crimp,or the like, or combinations thereof. Alternatively, the clamp may be anendless band with thermally frozen-in strain, which is tensioned byreleasing the strain and allowing the band to shrink onto the springliner, hose and fitting. In addition, tensioning band or hose clampwidth may vary. The proportionality of tensioning band width to linerwidth and liner contact width may vary.

Other known features of hose clamps may be incorporated if desiredwithout departing from the scope of the invention. For example, variousmeans of attaching the assembly to the hose, such as adhesive, avulcanizing patch, a locating tab, a locating clip, and the like may beincorporated. Cutouts or apertures for adjusting spring stiffness, orthe like may be incorporated.

In actual practice, a hose clamp with an annular spring liner is placedover the hose and fitting to be joined. Clamp diameter is reduced bymeans of the tensioning mechanism. Spring liner diameter is reducedproportionally to the clamp diameter reduction by increasing thecircumferential overlap length of the liner. As the combined hose clampand annular spring liner diameters decrease, radial pressure acting onthe underlying hose and fitting increase. Because of the shape of theliner, the radial pressure on the hose is amplified from that generatedby the clamp alone, while remaining relatively uniform in the hoseregion under the liner.

As the radial forces acting on the spring liner increase as a result ofincreased tension in the outer band, the spring liner deflects in such amanner that shoulders 5 deflect downward towards hose 11. This movementcan continue until the desired tension is achieved. However, themovement becomes limited at the point where the central rippled portion7 contacts (if ever) the inner face of the clamp band 1. The deflectionsare elastic, spring-like behavior. Therefore, the liner can respond tovariations in band tension and/or radial pressures as a spring. Thisspring behavior insures that the central rippled portion 7 exertssufficient radial pressure on the hose throughout the life of the clampinstallation.

As an example of a possible modification, it is envisioned that in oneembodiment of the invention, the inner face of the hose clamp couldinitially when assembled contact one shoulder of the spring liner, therebeing a gap between the inner face of the clamp and a second shoulder ofthe liner. As the hose clamp of this embodiment is tensioned, the gapbetween the inner face and the second shoulder would close asdeformation energy is stored in the spring liner, with the clamp perhapseven finally seating on the second shoulder.

The use of an embodiment of the invention has benefits. As mentionedpreviously, the force required to pull off the clamp may be increased,resulting in higher working pressure and better sealing. Also, the clamppressure is amplified relative to a band without a liner at a giventension. The generally flat central portion of the liner with onlyrelatively small ripples results in a more uniform pressure distributionboth around the hose and along the hose than for the prior art springliner having two inward ridges according to U.S. Pat. No. 7,302,741.This could be helpful for certain applications or embodiments.

Edge effects and relaxation or compression set effects within therubber, may make the results or advantages to be dependent on thedetails of the hose construction and materials which is being clamped.Thus, the benefits of the invention, and the comparative advantagesrelative to the prior art liner, may depend on the type of hose and thetype of application. The prior art liner, with its two larger ridgescould still give higher peak pressures immediately under the ridges.However, some types of hose or application may be better clamped with ahigher average pressure, but lower peak pressure.

Although the present invention and its advantages have been described indetail, it should be understood that various changes, substitutions, andalterations can be made herein without departing from the spirit andscope of the invention as defined by the appended claims. Moreover, thescope of the present application is not intended to be limited to theparticular embodiments of the process, machine, manufacture, compositionof matter, means, methods, and steps described in the specification. Asone of ordinary skill in the art will readily appreciate from thedisclosure of the present invention, processes, machines, manufacture,compositions of matter, means, methods, or steps, presently existing orlater to be developed that perform substantially the same function orachieve substantially the same result as the corresponding embodimentsdescribed herein may be utilized according to the present invention.Accordingly, the appended claims are intended to include within theirscope such processes, machines, manufacture, compositions of matter,means, methods, or steps. The invention disclosed herein may suitably bepracticed in the absence of any element that is not specificallydisclosed herein.

1. An annular spring liner, for a hose clamp having an inner face,comprising: a circumferential shoulder near an edge of said liner; and acentral, cylindrical, rippled, contact portion of smaller circumferencethan said shoulder; wherein said shoulder is adapted to abut said innerface.
 2. The spring liner of claim 1 further comprising acircumferential shoulder near each edge of said liner, wherein both saidshoulders abut said inner face.
 3. The spring liner of claim 2 whereinsaid rippled contact portion does not abut said inner face in theabsence of clamp tensioning forces.
 4. The spring liner of claim 3wherein said rippled contact portion is narrower than said inner face.5. The spring liner of claim 4 wherein said rippled contact portion hasa width in the range of 40% to 70% of the width of said inner face. 6.The spring liner of claim 4, further comprising on at least one edge aradially outwardly flared flange.
 7. The spring liner of claim 3,further comprising on each circumferential edge a radially outwardlyflared flange extending beyond the width of the inner face.
 8. Thespring liner of claim 1 wherein said liner has generally circular shapewith overlapping ends.
 9. The spring liner of claim 1 wherein saidrippled portion comprises ripples of generally sinusoidal shape.
 10. Thespring liner of claim 1 wherein said rippled portion comprises ripplesof saw-tooth shape.
 11. A hose clamp having an inner face and an annularspring liner, said liner comprising: a circumferential shoulder near anedge of said liner; and a central, cylindrical, rippled, contact portionof smaller circumference than said shoulder; wherein said shoulder isadapted to abut said inner face.
 12. The hose clamp of claim 11 furthercomprising a circumferential shoulder near each edge of said liner,wherein both said shoulders abut said inner face.
 13. The hose clamp ofclaim 12 wherein said rippled contact portion does not abut said innerface in the absence of clamp tensioning forces and a gap is definedthere between.
 14. The hose clamp of claim 13 wherein said rippledcontact portion is narrower than said inner face.
 15. The hose clamp ofclaim 14 wherein said rippled contact portion has a width in the rangeof 40% to 70% of the width of said inner face.
 16. The hose clamp ofclaim 14, further comprising on at least one edge a radially outwardlyflared flange.
 17. The hose clamp of claim 13, further comprising oneach circumferential edge a radially outwardly flared flange extendingbeyond the width of the inner face.
 18. The hose clamp of claim 10wherein said liner has generally circular shape with overlapping ends.19. The hose clamp of claim 10 wherein said rippled portion of saidspring liner comprises ripples of generally sinusoidal shape.
 20. Thehose clamp of claim 1 wherein said rippled portion of said spring linercomprises ripples of saw-tooth shape.
 21. The hose clamp of claim 13further comprising a tensioner.
 22. The hose clamp of claim 21 whereinsaid tensioner comprises a worm drive.